I see where you're coming from, Val. But lets say you're playing some covers in a band, and you're using a Mod50, with a setup like a T/D, with an SL2.
Lets say you're rocking a strat, and you want to do an SRV cover. T is set clean, deluxe is set to grind, but your SL2 is set for high gain. You do most of the song on the D side, but want to kick it up just a touch for a solo. In that case, the BB shines. Because switching over to the SL2 would be too drastic.
Don't get me wrong - I'll take a good tube amp tone over a pedal anyday. But I think that a good overdrive into a slightly crunchy fendery or marshall sounding amp definitely can be considered a legitimately good, useful tone in it's own right.